ipvlan: add ipvlan_route_v6_outbound() helper

Inspired by syzbot reports using a stack of multiple ipvlan devices.

Reduce stack size needed in ipvlan_process_v6_outbound() by moving
the flowi6 struct used for the route lookup in an non inlined
helper. ipvlan_route_v6_outbound() needs 120 bytes on the stack,
immediately reclaimed.

Also make sure ipvlan_process_v4_outbound() is not inlined.

We might also have to lower MAX_NEST_DEV, because only syzbot uses
setups with more than four stacked devices.

BUG: TASK stack guard page was hit at ffffc9000e803ff8 (stack is ffffc9000e804000..ffffc9000e808000)
stack guard page: 0000 [#1] SMP KASAN
CPU: 0 PID: 13442 Comm: syz-executor.4 Not tainted 6.1.52-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:kasan_check_range+0x4/0x2a0 mm/kasan/generic.c:188
Code: 48 01 c6 48 89 c7 e8 db 4e c1 03 31 c0 5d c3 cc 0f 0b eb 02 0f 0b b8 ea ff ff ff 5d c3 cc 00 00 cc cc 00 00 cc cc 55 48 89 e5 <41> 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 a4 01 00 00 48 89
RSP: 0018:ffffc9000e804000 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817e5bf2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff887c6568
RBP: ffffc9000e804000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92001d0080c
R13: dffffc0000000000 R14: ffffffff87e6b100 R15: 0000000000000000
FS: 00007fd0c55826c0(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000e803ff8 CR3: 0000000170ef7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<#DF>
</#DF>
<TASK>
[<ffffffff81f281d1>] __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
[<ffffffff817e5bf2>] instrument_atomic_read include/linux/instrumented.h:72 [inline]
[<ffffffff817e5bf2>] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
[<ffffffff817e5bf2>] cpumask_test_cpu include/linux/cpumask.h:506 [inline]
[<ffffffff817e5bf2>] cpu_online include/linux/cpumask.h:1092 [inline]
[<ffffffff817e5bf2>] trace_lock_acquire include/trace/events/lock.h:24 [inline]
[<ffffffff817e5bf2>] lock_acquire+0xe2/0x590 kernel/locking/lockdep.c:5632
[<ffffffff8563221e>] rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:306
[<ffffffff8561464d>] rcu_read_lock include/linux/rcupdate.h:747 [inline]
[<ffffffff8561464d>] ip6_pol_route+0x15d/0x1440 net/ipv6/route.c:2221
[<ffffffff85618120>] ip6_pol_route_output+0x50/0x80 net/ipv6/route.c:2606
[<ffffffff856f65b5>] pol_lookup_func include/net/ip6_fib.h:584 [inline]
[<ffffffff856f65b5>] fib6_rule_lookup+0x265/0x620 net/ipv6/fib6_rules.c:116
[<ffffffff85618009>] ip6_route_output_flags_noref+0x2d9/0x3a0 net/ipv6/route.c:2638
[<ffffffff8561821a>] ip6_route_output_flags+0xca/0x340 net/ipv6/route.c:2651
[<ffffffff838bd5a3>] ip6_route_output include/net/ip6_route.h:100 [inline]
[<ffffffff838bd5a3>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:473 [inline]
[<ffffffff838bd5a3>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bd5a3>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bd5a3>] ipvlan_queue_xmit+0xc33/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff84d4a65e>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff84d4a65e>] neigh_resolve_output+0x64e/0x750 net/core/neighbour.c:1560
[<ffffffff855ce503>] neigh_output include/net/neighbour.h:545 [inline]
[<ffffffff855ce503>] ip6_finish_output2+0x1643/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff855b9ce4>] dst_output include/net/dst.h:444 [inline]
[<ffffffff855b9ce4>] NF_HOOK include/linux/netfilter.h:309 [inline]
[<ffffffff855b9ce4>] ip6_xmit+0x11a4/0x1b20 net/ipv6/ip6_output.c:352
[<ffffffff8597984e>] sctp_v6_xmit+0x9ae/0x1230 net/sctp/ipv6.c:250
[<ffffffff8594623e>] sctp_packet_transmit+0x25de/0x2bc0 net/sctp/output.c:653
[<ffffffff858f5142>] sctp_packet_singleton+0x202/0x310 net/sctp/outqueue.c:783
[<ffffffff858ea411>] sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline]
[<ffffffff858ea411>] sctp_outq_flush+0x661/0x3d40 net/sctp/outqueue.c:1212
[<ffffffff858f02f9>] sctp_outq_uncork+0x79/0xb0 net/sctp/outqueue.c:764
[<ffffffff8589f060>] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
[<ffffffff8589f060>] sctp_do_sm+0x55c0/0x5c30 net/sctp/sm_sideeffect.c:1170
[<ffffffff85941567>] sctp_primitive_ASSOCIATE+0x97/0xc0 net/sctp/primitive.c:73
[<ffffffff859408b2>] sctp_sendmsg_to_asoc+0xf62/0x17b0 net/sctp/socket.c:1839
[<ffffffff85910b5e>] sctp_sendmsg+0x212e/0x33b0 net/sctp/socket.c:2029
[<ffffffff8544d559>] inet_sendmsg+0x149/0x310 net/ipv4/af_inet.c:849
[<ffffffff84c6c4d2>] sock_sendmsg_nosec net/socket.c:716 [inline]
[<ffffffff84c6c4d2>] sock_sendmsg net/socket.c:736 [inline]
[<ffffffff84c6c4d2>] ____sys_sendmsg+0x572/0x8c0 net/socket.c:2504
[<ffffffff84c6ca91>] ___sys_sendmsg net/socket.c:2558 [inline]
[<ffffffff84c6ca91>] __sys_sendmsg+0x271/0x360 net/socket.c:2587
[<ffffffff84c6cbff>] __do_sys_sendmsg net/socket.c:2596 [inline]
[<ffffffff84c6cbff>] __se_sys_sendmsg net/socket.c:2594 [inline]
[<ffffffff84c6cbff>] __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2594
[<ffffffff85b32553>] do_syscall_x64 arch/x86/entry/common.c:51 [inline]
[<ffffffff85b32553>] do_syscall_64+0x53/0x80 arch/x86/entry/common.c:84
[<ffffffff85c00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 2ad7bf3 ("ipvlan: Initial check-in of the IPVLAN driver.")
Reported-by: syzbot <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Mahesh Bandewar <[email protected]>
Cc: Willem de Bruijn <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Eric Dumazet

drivers/net/ipvlan/ipvlan_core.c

@@ -411,7 +411,7 @@ struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port, void *lyr3h,
 	return addr;
 }
 
-static int ipvlan_process_v4_outbound(struct sk_buff *skb)
+static noinline_for_stack int ipvlan_process_v4_outbound(struct sk_buff *skb)
 {
 	const struct iphdr *ip4h = ip_hdr(skb);
 	struct net_device *dev = skb->dev;
@@ -453,13 +453,11 @@ static int ipvlan_process_v4_outbound(struct sk_buff *skb)
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
-static int ipvlan_process_v6_outbound(struct sk_buff *skb)
+
+static noinline_for_stack int
+ipvlan_route_v6_outbound(struct net_device *dev, struct sk_buff *skb)
 {
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
-	struct net_device *dev = skb->dev;
-	struct net *net = dev_net(dev);
-	struct dst_entry *dst;
-	int err, ret = NET_XMIT_DROP;
 	struct flowi6 fl6 = {
 		.flowi6_oif = dev->ifindex,
 		.daddr = ip6h->daddr,
@@ -469,27 +467,38 @@ static int ipvlan_process_v6_outbound(struct sk_buff *skb)
 		.flowi6_mark = skb->mark,
 		.flowi6_proto = ip6h->nexthdr,
 	};
+	struct dst_entry *dst;
+	int err;
 
-	dst = ip6_route_output(net, NULL, &fl6);
-	if (dst->error) {
-		ret = dst->error;
+	dst = ip6_route_output(dev_net(dev), NULL, &fl6);
+	err = dst->error;
+	if (err) {
 		dst_release(dst);
-		goto err;
+		return err;
 	}
 	skb_dst_set(skb, dst);
+	return 0;
+}
+
+static int ipvlan_process_v6_outbound(struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+	int err, ret = NET_XMIT_DROP;
+
+	err = ipvlan_route_v6_outbound(dev, skb);
+	if (unlikely(err)) {
+		DEV_STATS_INC(dev, tx_errors);
+		kfree_skb(skb);
+		return err;
+	}
 
 	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 
-	err = ip6_local_out(net, skb->sk, skb);
+	err = ip6_local_out(dev_net(dev), skb->sk, skb);
 	if (unlikely(net_xmit_eval(err)))
 		DEV_STATS_INC(dev, tx_errors);
 	else
 		ret = NET_XMIT_SUCCESS;
-	goto out;
-err:
-	DEV_STATS_INC(dev, tx_errors);
-	kfree_skb(skb);
-out:
 	return ret;
 }
 #else